In recent years, the devices used to implement switching amplifiers have increased in performance, thereby improving audio fidelity. As the audio fidelity of switching amplifiers improves, switching amplifiers have been increasingly implemented in consumer electronics. Generally, switching amplifiers are high efficiency amplifiers that were initially used in electronic devices requiring power efficiency, such as mobile phones and other portable electronic devices.
However, switching amplifiers are increasingly being implemented in stationary electronic devices such as home entertainment devices (e.g., televisions, surround sound receivers, etc.). In such electronic devices, the switching amplifiers are implemented to have higher power output than switching amplifiers used in portable electronics. For example, switching amplifiers may be implemented in a high-fidelity surround sound receiver having a total power output of hundreds of watts. In such cases, switching amplifiers may implemented in place of linear amplifiers (e.g., a class A amplifier) because the large number of amplifiers required (e.g., seven amplifiers for surround sound) and the relatively low efficiency of class A amplifiers.
Furthermore, switching half-bridge amplifier circuits are commonly used in the output stage(s) of many types of electronic amplifiers, such as, for example, class-D audio amplifiers. In a typical configuration, a switching half-bridge amplifier, or output amplification stage, includes a high-side transistor and a low-side transistor. Field effect transistors (FETs) are commonly used to implement half-bridge amplifiers. In an example FET-based implementation, the output of the half-bridge amplifier is provided at the node at which the source of the high-side FET is coupled with the drain of the low-side FET.
During typical operation, the output of such a half-bridge amplifier is switched between a high-side voltage substantially equal to the drain voltage of the high-side FET and a low-side voltage substantially equal to the source voltage of the low-side FET. The output of the half-bridge amplifier is switched to the high-side voltage by switching both the high-side FET ON and the low-side FET OFF. Conversely, the output of the half-bridge amplifier is switched to the low-side output voltage by switching both the high-side FET OFF and the low-side FET ON. In other words, the high-side FET and the low-side FET are controlled in a complimentary, yet opposite, fashion. In many switching half-bridge amplifier implementations, transient spikes in the output voltage occur when the voltage output is switched from the high-side output voltage to the low-side output voltage, and vice versa.
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